If you got to go TK, then what i would do is start a new toon. With Elizabeth's buff, you can sp farm and get your skills faster now. When your new TK hits level 25 and advances he can borrow the armor from your RK now.
You go to Crean, change your class, and LOSE the sp and you will find that sp farming is a lot harder at higher levels. So you will have to suck it up and start a new toon. That is what I would suggest.
You could buy a reset card if you are rich now. lol Not me.